§412.620. Patient classification system.

A patient classification system is used to classify patients in inpatient rehabilitation facilities into mutually exclusive case-mix groups.

For purposes of this subpart, case-mix groups are classes of Medicare patient discharges by functional-related groups that are based on a patient's impairment, age, comorbidities, functional capabilities, and other factors that may improve the ability of the functional-related groups to estimate variations in resource use.

Data from admission assessments under § 412.610(c)(1) are used to classify a Medicare patient into an appropriate case-mix group.

Data from the discharge assessment under § 412.610(c)(2) are used to determine the weighting factors under paragraph (b)(4) of this section.

General. An appropriate weight is assigned to each case-mix group that measures the relative difference in facility resource intensity among the various case-mix groups.

Short-stay outliers. We will determine a weighting factor or factors for patients that are discharged and not transferred (as defined in § 412.602) within a number of days from admission as specified by us.

Patients who expire. We will determine a weighting factor or factors for patients who expire within a number of days from admission as specified by us.

Comorbidities. We will determine a weighting factor or factors to account for the presence of a comorbidity, as defined in § 412.602, that is relevant to resource use in the classification system.